Horsepower Old vs New Outboards ?

It seems I recall that outboards used to be rated for horsepower at the
crank, and now they are rated at the prop shaft. The net difference being
that a newer motor actually develops more power for the same rating than an
older motor.

Is that true?

If so, at about what time did motors start being rated at the prop shaft?

The reason I ask is that I just got my Whacko (Waco) on the water.

http://tinyurl.com/yqcs7

They way it is configured it is rated for a 50HP outboard. I have an older
Froce 50 on it that I picked up from Ebay. It runs great, but I was
wondering if shopping for a newer motor might get me a little better push.

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This is true. I believe the change occurred in 1985 but may be wrong on the
exact year.
A new outboard does produce about 15% more than an old one. Plus the fact
that a new outboard can be rated +/- 10%. So a 150 could actually be a 165
and still be rated at 150. Plus the fact that a rating is at a certain rpm.
Take for example a 200 hp 1990 model Evinrude. They were rated at 5000
rpms. They would actually produce about 225 at 6000 rpms.

Every motor is different however. In your case, a new Merc 50 would
definitely be stronger than that old force. But it probably would not be
worth the cost of a new engine for the 5 mph top end difference. Most bang
for the buck would be to get a good SS prop that will give you a lot more
bow lift.

Tony
my boats at <a style='text-decoration: underline;' href="http://t.thomas.home.mchsi.com" target="_blank">http://t.thomas.home.mchsi.com</a>



"Bob La Londe" <usenet.TakeThisOut@diycomponents.com> wrote in message
news:U4-dnc2ci9wsTs7d4p2dnA@adelphia.com...
 > It seems I recall that outboards used to be rated for horsepower at the
 > crank, and now they are rated at the prop shaft. The net difference being
 > that a newer motor actually develops more power for the same rating than
an
 > older motor.
 >
 > Is that true?
 >
 > If so, at about what time did motors start being rated at the prop shaft?
 >
 > The reason I ask is that I just got my Whacko (Waco) on the water.
 >
<font color=purple> > <a style='text-decoration: underline;' href="http://tinyurl.com/yqcs7</font" target="_blank">http://tinyurl.com/yqcs7</font</a>>
 >
 > They way it is configured it is rated for a 50HP outboard. I have an
older
 > Froce 50 on it that I picked up from Ebay. It runs great, but I was
 > wondering if shopping for a newer motor might get me a little better push.
 >
 > --
 > Public Fishing Forums
 > Fishing Link Index
<font color=purple> > <a style='text-decoration: underline;' href="http://www.YumaBassMan.com</font" target="_blank">www.YumaBassMan.com</font</a>>
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